Spicy lamb burgers with tzatziki (or hummus) recipe

SERVES 4 INGREDIENTS 1 small onion or large shallot 2 tbsp mint leaves 2 tbsp flat-leaf parsley 3 garlic cloves 500g lamb mince 1 tsp ground coriander 1 tsp ground cumin ½ tsp chilli flakes ¼ tsp cinnamon 2 tsp sea salt 1 tsp black pepper Olive oil, for brushing 4 wholemeal pitta breads 1 tub tzatziki (or …